Mozilla is backing a move that would nullify copyright infringement charges against people who "jailbreak" their iPhones, a practice that Apple Inc. considers against the law.

In comments submitted to the U.S. Copyright Office , the maker of Firefox said it supports the Electronic Frontier Foundation (EFF) in its request for an exemption to the Digital Millennium Copyright Act (DMCA). The EFF wants the Copyright Office to let users jailbreak their phones without fear of copyright infringement penalties.

Apple opposes the exemption, and in its own filing with the Copyright Office, has said that jailbreaking is a violation of copyright laws that protect its software.

"This is not us criticizing Apple," John Lilly, Mozilla's CEO, said in an interview Monday. "But it's the principle of the thing. Choice is good for users, and choice shouldn't be criminalized. The Internet is too important for all of us for that."

"Jailbreak" is the term used to describe circumventing the DRM technology on a cell phone so that the user can install third-party applications not authorized by the phone's maker or the mobile carrier. The term was popularized by iPhone owners after several groups of programmers figured out how to hack the first-generation iPhone's operating system.

Although it never mentioned the iPhone by name in its comments, Mozilla made no bones about the danger it sees if a company like Apple is the sole gatekeeper of a smartphone. "By controlling the software that can be installed on these cellular phones, these companies can limit and control the type of programs and functionality that is available to users of their devices," Mozilla's general counsel, Harvey Anderson, wrote in the comments submitted to the Copyright Office (download PDF).

Anderson said that the DRM technology used to prevent people from installing software has a "chilling effect on users and innovation" because they are afraid that jailbreaking their phones is illegal.

He went on to argue that smartphones are akin to a computer, and because they can be used to access the Internet, should not be limited to the software authorized by the handset maker and/or the mobile service provider. "These devices contain Internet Web browser, and are therefore effectively users' doorway to the Internet -- a public commons," Anderson said. "Consumers should be entitled to use any software program they choose to access the Internet."

Apple includes a version of its own Safari browser on the iPhone, and decides which third-party applications can be downloaded from its App Store online mart, the only authorized distribution channel. In the past, Apple has rejected programs it says duplicate its own iPhone software, a notion that is reportedly spelled out in the iPhone's SDK licensing agreement. So far, no major rival to Safari has been offered to users through the App Store.

As things stand now, Mozilla would be unlikely to craft a version of Firefox for the iPhone, said Lilly. "The SDK is very clear that Flash and Firefox and other runtimes are not welcome on the iPhone," he said. "Given the choice, would we work on a platform where the sole company controlling it makes us unwelcome, or would we work on a platform, like Linux, where we are welcome? The answer is going to be easy for us."

Mozilla is currently working on a mobile browser based on the same code that drives Firefox. Code-named "Fennec," the browser is in the preliminary stages of development. The first build for Windows Mobile-powered phones, for instance, was released only last week.

Although he declined to get into product development specifics, Lilly said he doubts Mozilla would venture into the iPhone even if the Copyright Office grants the DMCA exemption over jailbreaking.

Opera Software ASA, a Norwegian company noted for its mobile browser, has come to the same decision. According to CEO Jon von Tetzchner, Opera considered, then abandoned development for the iPhone when it realized that Apple's SDK license barred other browsers.

Mozilla wasn't the only technology company or developer who weighed in on the side of the EFF. Skype Communications, the eBay Inc. subsidiary known for its VoIP software, for example, also backed the exemption request. "Copyright law should not interfere with a user using his or her phone to run Skype and enjoy the benefits of low- or no-cost long-distance and international calling," Skype said. So did Jay Freeman, the developer of Cydia, the open source application installer that acts as an App Store substitute for jailbroken iPhones.

Claiming that his program is installed on 1.6 million iPhones worldwide, a quarter of them in the United States, Freeman wasted no time blasting Apple's software restrictions. "They have denied competing mail applications, competing camera applications and competing mapping systems," Freeman said in comments he submitted supporting the EFF request (download PDF). "They also have exerted control over what they [feel] to be acceptable content, sometimes vacillating (first denying any application using the word 'fart,' then allowing one in, which rapidly becomes the #1 most popular application in the store."

The danger of a gatekeeper like Apple on the iPhone is that innovation is stifled, Lilly argued. "These vertical silos don't enable innovation," he said. "And technology diffusion takes much longer, if it ever happens."